The account includes retail advertising at petrol pumps and point-of-sale and print activity at Shell's forecourts across Europe. The five-year contract covers 19 markets including UK, France and Poland.
Proximity won the account in 2003 after a seven-way pitch involving Iris, Triangle, Tullo Marshall Warren, KLP Euro RSCG, Toast and JWT.
Tequila, the previous incumbent, resigned the account when Shell prevented the agency from working with competitors, including markets where it did not hold the business.
The review will not affect Shell’s relationship with its advertising agency JWT. MediaCom handles Shell's media planning and buying account.
Proximity board account director Jo Boulter said: "Despite being the incumbent agency we worked hard to bring fresh ideas to our proposal and we believe that it was this that made us the winning agency."